A Soupçon of SciComm with Vivek Nityananda on stereo vision in Praying Mantis

I am Vivek Nityananda, Postdoctoral Research Associate at Newcastle University where I am affiliated with the Centre for Behaviour and Evolution. The main focus of my research is on how animals use their senses and cognition and how that links to their ecology and evolution. I’ve worked on several systems including bush crickets, frogs, bees and humans. I’m currently researching stereo vision in praying mantises. I’ve also begun a collaboration to investigate the evolution of self-deception in humans and other animals

How did you get where you are right now?

After completing an integrated M. Sc. in Biological Sciences at BITS, Pilani, I went on to do a PhD in animal behaviour investigating acoustic signalling in bush crickets with Rohini Balakrishan. This was at the Centre for Ecological Sciences, Indian Institute of Science, Bengaluru. After my PhD I got a postdoctoral position to study hearing in frogs with Mark Bee at the University of Minnesota in St Paul, USA. I had also applied for HFSP and Marie Curie fellowships which I was awarded. That helped me move to London and work with Lars Chittka at Queen Mary University of London on visual search and attention in bees. On completing this project, I interviewed for my current position looking at mantis stereo vision at Newcastle University. In 2016, I also spent four months at the Wissenschaftskolleg zu Berlin on a College for Life Sciences fellowship to research the evolution of attention.

Imagine you have the power to go back in time to when you were in high school or undergrad. You get to explain a single cool finding/concept from your field of science/profession to your younger self. Can you do it in an easy to understand manner with as little scientific jargon as possible? (500 words limit)

Here’s a short description about stereo vision and how it works in the praying mantis. Animals (including humans) use several visual cues to gauge their distance to different objects. These include perspective, focus, movement and whether one object occludes another. One of the more specialized ways of telling depth is through stereo vision. Stereo vision involves comparing the slightly different views of each eye and using the difference to tell how far objects are. This is what is manipulated to give you an illusion in a 3D cinema. Closing one eye and then the other will show you how the visual scene shifts. Object that are closer to you shift more and objects further away shift less – this is the basis of depth calculation by stereo vision. In order to make this calculation, our brains need to be able to match an object seen by one eye with the same object seen by the other eye. We do this through a complex calculation that matches the patterns of darkness and brightness in the world around us. But, what about other animals that have stereo vision?

One such animal is the praying mantis, the only insect known to have stereo vision. Mantises are evolutionary distant to humans and have evolved vision independently. It could therefore be possible that they had evolved a completely different way of processing stereo cues. Our recent research investigated this and found that unlike primates and owls, mantises don’t match the stationary patterns of darkness and brightness across their two eyes. Instead, their brains look for change in each eye and match objects defined by this change. This would typically mean matching moving objects in each eye and using the difference between their positions to calculate depth. This is therefore a completely new form of stereo vision which is simpler than ours but works effectively for mantises. In fact, it can detect depth in stimuli where humans fail to do so – such as when patterns don’t match in both eyes.

Looking at this more broadly, this is a great example of how very different mechanisms can underlie seemingly similar abilities. Each animal evolves a mechanism best adapted to its biology (e.g. brain size) and ecology (e.g. moving prey). The same ideas could be applied to several sensory phenomena as well as to cognition. Animals, including insects, could achieve cognitive feats seen in humans using different, potentially smarter or more efficient mechanisms. There’s much we can still learn from them.